In line with the exponential increase in the average amount of data used by mobile users, there is an increasing user demand for higher data rates. Methods capable of providing a high data rate may be roughly classified into a method of performing communication using a wider frequency band and a method of increasing the frequency usage efficiency. The latter method has a lot of difficulty in providing a higher average data rate since it is hard to further increase the frequency usage efficiency through the technology improvements as the currently available communication technologies have already provided the frequency usage efficiency close to its theoretical limit. Therefore, an efficient way to increase the data rate is to provide data services over a wider frequency band.
In order to provide data services over a wide frequency band, available frequency bands need to be considered, and millimeter-wave bands of 30 GHz or higher are commonly used, because the bands of 1 GHz or higher, capable of broadband communication, are limited. In these high frequency bands, unlike in the 2 GHz band used by the cellular systems according to the related art, the signal attenuation may significantly increase with the increase in the distance, causing a significant reduction in service coverage of a base station.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.